1. Field
The disclosed technology relates generally to a display device and a driving method thereof More particularly, the disclosed technology relates generally to an organic light emitting diode (OLED) display and a driving method thereof.
2. Description of the Related Technology
A display device includes a display panel which has a plurality of pixels arranged in a matrix. The display panel includes a plurality of scan lines formed in a row direction and a plurality of data lines formed in a column direction. The plurality of scan lines and the plurality of data lines cross each other. Each of the plurality of pixels is driven by a scan signal and a data signal transmitted from a corresponding scan line and data line.
The display device is either a passive matrix type of light emitting display device or an active matrix type of light emitting display device according to a driving scheme of the pixels. Active matrix displays, in which pixels are selectively lit according to resolution, contrast, and operation speed, are primarily used.
The display device is used as a display device of portable information terminals such as a personal computer, a mobile phone, a PDA, or the like, or monitors of various types of information equipment. An LCD using a liquid crystal panel, an organic light emitting display device using an organic light emitting device, a PDP using a plasma panel, etc., are known. In recent years, various light emitting display devices having smaller weight and volume than cathode ray tubes have been developed, and in particular, the organic light emitting display device has excellent emission efficiency, luminance, viewing angle, and rapid response speed and has attracted public attention.
The driving method of the organic light emitting diode (OLED) display includes a voltage driving method and a current driving method. The voltage driving method divides a predetermined voltage into a plurality of gray voltages, and one of the divided gray voltages is applied to the pixel as one data signal thereby displaying an image. This voltage driving method has a limit for displaying uniform images due to the characteristic deviation of the driving transistor provided in each pixel.
In contrast, the current driving method supplies a predetermined current as the data signal to the pixel, thereby displaying the image. The current driving method may display uniform images regardless of the characteristic deviation of the driving transistor. However, it is difficult to charge the desired voltage to the pixel during the required time in the current driving method. Accordingly, it is difficult to apply the current driving method to a display device of a large area, and a plurality of gray scales displayed through fine currents to display images of a high resolution.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.